package com.java8;

/**
 * <p>Description: [类功能描述]</p>
 * Created on 2020/12/24
 *
 * @author <a href="mailto: 819712047@qq.com">谢振东 </a>
 * @version 1.0
 */
public class test1 {
    public static void main(String[] args) {
        Atest a = new Atest();
        String userName = (a == null ? "" : a.getUserName());
        System.out.println("1:" + userName);
        userName = a == null ? "" : a.getUserName();
        System.out.println("2:" + userName);
        a = null;
        userName = (a == null ? "" : a.getUserName());
        System.out.println("3:" + userName);
        userName = a == null ? "" : a.getUserName();
        System.out.println("4:" + userName);
    }


}
